The overall percentages are correct. That's what they are...overall percentages.
The way someone can use overall percentages is to compare yourself against the norm. This is a waste of time if we are talking about the lottery because there are no variables involved.The overall percentage chance for winning tells the whole story, period.
But if you are looking to get into College X, and the admissions rate is 25%, and the average GPA is 3.5, and the average SAT is 1700...anyone could plug in their own academic stats and draw a presumption about whether their chances were better or worse than 25%. Or they could decide to apply or not, without this information.
If anyone out there is interpreting overall stats to be applicable to every single individual, then I would caution against that. After all, the overall 2012 American League batting average was .255. Odds of getting a hit, based on the definition of AB, was 25.5%. But we all know that everyone did not hit .255. Better hitters hit better, worse hitters hit worse. .255 was just the overall average